This invention relates to a battery (also known as an accumulator), particularly, but not exclusively, to a battery of the lead-acid type.
In a known battery construction, the positive and negative plates are all connected together to positive and negative terminals respectively by means of connecting straps. The plates are positioned in a box-like container, usually of moulded plastics material, the top of the box being closed by a lid, the terminals projecting through respective apertures in the lid. The lid is sealed to the box and the terminals are sealed within the respective apertures to prevent unwanted escape of fluid e.g. acid or fumes. Two (or the appropriate number) of recesses are formed in the lid and the apertures are formed at the bases of the recesses so that the respective terminals protrude through the apertures into the recesses. When assembling the battery the lid is sealingly connected to the box using a suitable settable material e.g. epoxy resin. Next a seal is placed in the base of each recess to surround the respective terminal and the recess is partially filled with settable sealant so as to cover the seal but leave the upper part of the terminal clear. The construction so formed has the disadvantages that it is complex and its assembly has to be carried out in several stages.
It is an object of the present invention to provide an alternative battery construction and method of assembly which does not suffer from or suffers less from the aforementioned disadvantages.
In accordance with the invention a battery comprises positive and negative plates, two connecting straps, one electrically connected to the positive plates and the other to the negative plates, the plates and straps being enclosed in a box with a lid, two terminals, each one electrically connected to a respective connecting strap, the terminals each projecting through a respective aperture in the lid and surrounded by a seal between the lid and the respective connecting strap, each of which straps has a formation which fits with a corresponding formation on the underside of the lid adjacent the respective aperture with a small gap therebetween, sealant being located in the small gap.
Preferably the formation on the lid and/or the formation on the connecting strap include locating means for the seal, which may be an O-ring. The sealant is preferably seftable and may comprise an epoxy resin.
The lid and the box may be formed with inter-fitting portions e.g. a groove in the lid and a correspondingly shaped edge to the box which may be provided with settable sealant which when fitted together seal the lid to the box. The aforesaid portions on the lid and box and the formations on the connecting straps and the underside of the lid are so constructed and arranged that on bringing the lid and box, which contains the plates and connecting straps, together for closure, the portions and formations fit together simultaneously.
The formations on the lid and/or on the connecting straps preferably include a sealant reservoir so constructed and arranged that on bringing the lid and box, which contains the plates and connecting straps, together for closure sealant is displaced from the reservoir and flows into and fills the small gap. Further preferably the sealant flows around and encapsulates the connecting straps.
In accordance with another aspect of the invention a method of assembling a battery having positive and negative plates, two connecting straps, one electrically connected to the positive plates and the other to the negative plates, the plates and straps being enclosed in a box with a lid, and two terminals, each one protruding through a respective aperture in the lid and being electrically connected to a respective connecting strap comprises the steps of:
providing a formation on each connecting strap,
providing a corresponding formation on the underside of the lid adjacent the respective aperture,
positioning two seals, one for each terminal, either on the connecting strap or on the underside of the lid,
providing sealant on each formation on the lid and/or on each formation on the straps,
bringing the lid and box together for closure to cause the formations on the connecting straps to fit with the corresponding formations on the lid and to cause the sealant to flow into and filling a small gap between the formations, and allowing the sealant to set.
Preferably one or each of the formations is formed to include a locating means for the seal which may be an O-ring.
Preferably the method may further comprise the steps of: providing the lid and box with inter-fitting portions, applying a settable sealant thereto, and bringing the lid and box together for closure whereby the portions on the lid and the box and the formations on the connecting straps and the underside of the lid fit together simultaneously.
The method may further comprise the step of providing the formations on each connecting strap and/or the formation on the underside of the lid with a sealant reservoir, supplying the reservoir with sealant and, on bringing the lid and box together for closure, causing the sealant to be displaced from the reservoir and flow into the small gap between the formations. Further preferably, the step of bringing the lid and box together for closure also causes the sealant to flow around and encapsulate each connecting strap.